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Don't call WalkGetAttr for walk(names=[]).

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PiperOrigin-RevId: 235587729
Change-Id: I37074416b10a30ca3a00d11bcde338d8d979beaf
This commit is contained in:
Jamie Liu
2019-02-25 13:03:56 -08:00
committed by Shentubot
parent 10426e0f31
commit 41167e6c50
1 changed files with 32 additions and 16 deletions
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pkg/p9/handlers.go
+32 -16
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@@ -237,7 +237,7 @@ func (t *Tattach) handle(cs *connState) message {
// We want the same traversal checks to apply on attach, so always
// attach at the root and use the regular walk paths.
names := strings.Split(t.Auth.AttachName, "/")
_, newRef, _, attr, err := doWalk(cs, root, names)
_, newRef, _, _, err := doWalk(cs, root, names, false)
if err != nil {
return newErr(err)
}
@@ -996,24 +996,38 @@ func (t *Tflushf) handle(cs *connState) message {
// walkOne walks zero or one path elements.
//
// The slice passed as qids is append and returned.
func walkOne(qids []QID, from File, names []string) ([]QID, File, AttrMask, Attr, error) {
func walkOne(qids []QID, from File, names []string, getattr bool) ([]QID, File, AttrMask, Attr, error) {
if len(names) > 1 {
// We require exactly zero or one elements.
return nil, nil, AttrMask{}, Attr{}, syscall.EINVAL
}
var localQIDs []QID
localQIDs, sf, valid, attr, err := from.WalkGetAttr(names)
if err == syscall.ENOSYS {
var (
localQIDs []QID
sf File
valid AttrMask
attr Attr
err error
)
switch {
case getattr:
localQIDs, sf, valid, attr, err = from.WalkGetAttr(names)
// Can't put fallthrough in the if because Go.
if err != syscall.ENOSYS {
break
}
fallthrough
default:
localQIDs, sf, err = from.Walk(names)
if err != nil {
// No way to walk this element.
return nil, nil, AttrMask{}, Attr{}, err
break
}
// Need a manual getattr.
_, valid, attr, err = sf.GetAttr(AttrMaskAll())
if err != nil {
// Don't leak the file.
sf.Close()
if getattr {
_, valid, attr, err = sf.GetAttr(AttrMaskAll())
if err != nil {
// Don't leak the file.
sf.Close()
}
}
}
if err != nil {
@@ -1033,7 +1047,7 @@ func walkOne(qids []QID, from File, names []string) ([]QID, File, AttrMask, Attr
// This enforces that all intermediate nodes are walkable (directories). The
// fidRef returned (newRef) has a reference associated with it that is now
// owned by the caller and must be handled appropriately.
func doWalk(cs *connState, ref *fidRef, names []string) (qids []QID, newRef *fidRef, valid AttrMask, attr Attr, err error) {
func doWalk(cs *connState, ref *fidRef, names []string, getattr bool) (qids []QID, newRef *fidRef, valid AttrMask, attr Attr, err error) {
// Check the names.
for _, name := range names {
err = checkSafeName(name)
@@ -1054,7 +1068,7 @@ func doWalk(cs *connState, ref *fidRef, names []string) (qids []QID, newRef *fid
var sf File // Temporary.
if err := ref.maybeParent().safelyRead(func() (err error) {
// Clone the single element.
qids, sf, valid, attr, err = walkOne(nil, ref.file, nil)
qids, sf, valid, attr, err = walkOne(nil, ref.file, nil, getattr)
if err != nil {
return err
}
@@ -1101,7 +1115,9 @@ func doWalk(cs *connState, ref *fidRef, names []string) (qids []QID, newRef *fid
var sf File // Temporary.
if err := walkRef.safelyRead(func() (err error) {
qids, sf, valid, attr, err = walkOne(qids, walkRef.file, names[i:i+1])
// Pass getattr = true to walkOne since we need the file type for
// newRef.
qids, sf, valid, attr, err = walkOne(qids, walkRef.file, names[i:i+1], true)
if err != nil {
return err
}
@@ -1146,7 +1162,7 @@ func (t *Twalk) handle(cs *connState) message {
defer ref.DecRef()
// Do the walk.
qids, newRef, _, _, err := doWalk(cs, ref, t.Names)
qids, newRef, _, _, err := doWalk(cs, ref, t.Names, false)
if err != nil {
return newErr(err)
}
@@ -1167,7 +1183,7 @@ func (t *Twalkgetattr) handle(cs *connState) message {
defer ref.DecRef()
// Do the walk.
qids, newRef, valid, attr, err := doWalk(cs, ref, t.Names)
qids, newRef, valid, attr, err := doWalk(cs, ref, t.Names, true)
if err != nil {
return newErr(err)
}